Date of this Version
Published in Micrometeorology in Agricultural Systems (2005) Agronomy Monograph no. 47: 155-177.
Freezing and thawing of soil is a common occurrence throughout the world. Indeed, approximately 50% of the Earth landmass is frozen at some time during the annual cycle, with 20% of the land underlain by permafrost (Sharratt et al., 1997). Seasonal freezing of soils with sparse vegetation and snow cover can occur to depths of 3.5 m (Kennedy & Sharratt, 1997; Shul’gin, 1965) while seasonal frost has been found to penetrate to depths of >6 m below paved runways (Carlson & Kersten, 1953). The extensiveness of soil freezing and the impact of freezing and thawing on the physical, chemical, and biological properties of soils demand a thorough assessment as to the timing and depth to which freezing occurs in soil.